Small Favor
"Not having it could have gotten me killed, too," I said. "And then you'd have wasted all that time you've put in trying to recruit me to be the next Winter Knight."
"Nonsense," Mab said. "If you died, I would simply recruit your brother. He would be well motivated to seek revenge upon your killers."
LordDresden2
That's a direct statement on Mab's part. Not an implication, or a suggestion, or a hint, it's a direct declarative statement. Either she means it...or she uttered a falsehood, which as far as know she simply can't.
This is also from Small Favor Page 402
Quote
"He isn't mortal," I said quietly. "I thought Knights had to be mortals,""He is in love," Grimalkin mrowled for Mab. "That makes him mortal enough for me." She tilted her head. Though I suppose I might make him an offer, while you yet live. He would give much to hold his love again, would he not?"
You are correct that was a declarative statement by Mab. However as you can see when Harry says Knights have to be mortal. Mab hedges her bets, because Thomas is in love,
that makes him mortal enough for her. Then Mab hints that a bargain that could be made with Thomas so he could hold Justine. This fogs up what the truth is just a bit, while Mab isn't exactly lying to Harry, she isn't exactly telling the truth either.. Though by her standards she is telling the truth, yes, she could
recruit Thomas to be her Knight, that isn't the same as
make Thomas her Knight.. However just the suggestion that she would recruit Thomas, puts pressure on Harry to become her Knight. Which is what Mab is really after.
